Manufacture of leather belting



Oct. 18,- 1949. I. DICKINSON MANUFACTURE OF LEATHER BELTING Filed Jan. 21, 1947 Patented Oct. 18, 1949 MANUFACTURE OF LEATHER BELTIN G Ingram Dickinson,

Atlanta, Ga.,

assignor to Southern Belting Company, Atlanta, Ga., a corporation of Georgia Application January 21, 1947, Serial No. 723,279

3 Claims.

This invention comprises an improved method of adhesively bonding together pieces of leather and. especially concerns a novel cement impregnating treatment adapted substantially to increase the strength of the resulting bond. Leather belting is formed by adhesively bonding together in end to end relation many short strips of leather skived off at their ends to form overlapping joint shaving beveled surfaces in face to face contact; and multi-ply belts are made by bonding together in face to face contact two or more plies fashioned in the same manner. The primary object of my invention is to provide an improved method of preparing and bonding together such strips and plies to produce belting of substantially increased strength.

In preparing leather for bonding, the faces to be bonded are first roughened and a coating of cement is then applied to these faces. I have discovered that a deeper and more uniform penetration of the cement into the fibres of leather is obtained by heating the leather and evaporating the moisture therefrom before applying the cement, and by preventing condensation of moisture at the coated surfaces during the coating and drying operations. I effect this treatment by subjecting the roughened surfaces, immediately prior to the coating operation, to the action of heating raising the temperature of the leather, above 100 F., sufficiently to expand the air and evaporate moisture from the leather and provide stored heat that will prevent condensation of moisture at said surfaces during the subsequent coating and drying operation, and I have furthermore discovered that a substantially superior product is obtained and my novel method advantageously practiced by employing infra-red heat rays directed onto the surfaces to be coated, all as hereinafter more specifically described.

The method of my invention is applicable to the bonding of strips of leather skived off at their ends and lapped in end to end relation and to the bonding together of two or more plies in face to face contact, and my novel method is applicable in continuous form to the latter. In this application of the invention, the strip of belting to be plied is fed along a predetermined path where it is subjected to the action of heat and treated while hot with a coating of cement. A treatment of this nature, preferably employing infra-red heating units, comprises a further feature of the invention.

These and other features of the invention will be best understood and appreciated from the fol lowing description of preferred applications thereof selected for purposes of illustration and shown in the accompanying drawings in which Fig. 1 is a plan view, partially broken away, of apparatus that may be employed in practicing my invention.

Fig. 2 is a fragmentary side elevation of the apparatus.

Fig. 3 is a sectional view taken on line 11 of Fig. 2,

Fig. 4 is a fragmentary view of a leather strip treated in the apparatus, and

Fig. 5 is a sectional view through two plies of belting held in face to face contact by and between two pressure surfaces.

I have found that a heating of the strips evaporates and so largely removes the moisture from the leather and expands the air therein to such a degree that when cement is applied it penetrates more deeply into the interstices of the fibres. Also the heat retained by the leather prevents lowering of the temperature below the dew point during the coating operation and particularly during the drying operation when the leather is cooled by evaporation of the solvent, thereby preventing the condensation of the moisture on the cement-coated surfaces of the leather.

In Figs. l-5 is illustrated apparatus for treating continuous plies of leather belting formed by joining the pieces l4 together, which treated plies are to be adhesively united in face to face contact in producing a multi-ply belt. This apparatus comprises a table 40 supported on legs 42 and carrying two adjustable guides 44 for receiving and guiding the work. A housing 46 provided with a pivoted cover 48 carrying two banks of infra-red lamps 50 is disposed above the left hand end of the table. A coil 52 of single ply belting 54 to be treated is shown as supported on a frame 56. The belting is passed from the coil 52 through guide rolls 58 to the table beneath the" housing. The belting includes in its length one or more lap joints 60 and passes between pressure rolls 64 to a reel 56 located at the far end of the table. The rolls and reel are operated by an electric motor 68 through belts l0 and 12, a slip clutch 13 being provided in the drive to the reel.

The surface of ply 54 to be coated is previously roughened and is drawn from the coil 52 and along the table by the rolls 64 and reel 66. The lamps 58 and the motor 68 are under the control of a switch 14 located adjacent to the operator position rearwardly of the housing 46. When the belting ply 54 is drawn from the roll 52 it passes first beneath the lamps 50 and thence along the ply as it emerges from the housing. and. isheated.

to the desired temperature. The coated ply thereafter continues along the table for aperiod sutficient to dry the coating by the time it reaches the rolls 64. After passing these rolls the coated ply is wound onto the reel 66. The switch 14 controls both the lamps 50 and the motor 68 so that the lamps are automatically turned off when the motor is stopped, it being understood that theoperation is ordinarily performed withthe ply in continuous feeding motionalong the table. The adjustment of the lamps andfeeding speed is such that there is no danger of scorching the leather while it is in motion, and the possibility of allowing the leatherto come to rest beneath the lamps is obviated. by placing both themotor and. the=1amps under'the conjoint control of the switch 14.

When two coated plies are to be adhesively joined together an additional-coating of cement isapplied to the surfaces 15. coated on the table 40/ and these two faces are then brought into contact and held under pressure between pressure. surfaces 16, as illustrated in Fig. 9, until the cement begins toset. The belting is then removed fromthe press and allowed todry for a period of six to twenty-four. hours.

I havefound that bonds made. in accordance withm processare 50% to. 200% stronger than bonds otherwise made in accordance with stand.- ard known practice, the increase in added strength varying with the grade and. tannageof leather used. The heat, especially when. applied by infra-redheat rays to the face to be coated, expands the air and evaporates the moisture from the leather and provides stored heat preventing the condensation of moisture at said. face during the coating and drying operations. Such treatment notonly facilitates deeper andmore complete penetration of the cement into. the leather but also. insures that the adhesivebond. shall'beformed without the presence ofimoisture either initially present in the leather or deposited from a humid atmosphere.

It will be understood, moreover, that in many instances it isdesirable to apply. two coats of cement, first a priming or sizing coating, and then a final coating, and that the surfaces to be cementedmay be heated both before the application of the priming coating and before the ap-.

plication of'the final coating;

While the application of my process to the manufacture of leather belting has been emphasized hereinabove, it will be understood that it has also a useful application in cementing together leather pieces in other industries, for example, in the shoemaking industry.

Having thus disclosed my invention and described in detail an illustrative manner of practising it; I claim as new and desire to secure by Letters Patent:

1. A continuous method of preparing a strip of leather for adhesive bonding which includes the steps of roughening one face of the strip, feeding thestrip along a predetermined path upon a supportingsurface, subjecting the strip while in motion to the action' of heat suflicient to raise its temperature above F. while moving in a preliminary portion of said path, applying a coating of cement to the roughened face of the strip im-' mediately following the heating operation, conjointly controlling: both the feeding movement and the heating of. the leather, and drying the coating of cement by moving the coated strip along a subsequent portionof the path.

2. The continuous method defined in claim. 1, further characterized by the application-of infrared rays directed upon successive areas of the roughened'face of the strip for a PGIiOdlOf time approximating one and'one-half minutes andat an intensity raising the temperature of themov ing leather toapproximately F.

3. The continuous method of making multiply leather belting. which includes the stepsofadvancing a single. lap-jointed ply of beltingv leather: along a horizontal path upon an supporting surface, subjecting theexposed face of' the ply while in motion to infra-red rays as the. ply

enters'said path, thereby evaporating moisture from-the leather and storing up heat therein, applying a solvent-containing cement to-the heated surface of the moving leather ply as it passes beyond the heating stage,. conjointly controlling both the feeding movement andthe heating of the leather, and continuing to advance the leather in the 'samehorizontal pathuntil the cement has dried, meanwhile maintaining the leather above the. dew pointv of the surrounding. atmosphere by the heat stored within it.

INGRAM DICKINSON.

REFERENCES CITED.

The following references are of record in thefile of this patent:

UNITED STATES PATEN'IS Number Name Date" 1,048,877 Rampichini Dec..31, 1912 1,325,075 Byers- Dec. 16, 1919 2,212,522 Hart Aug; 27, 1940 2,3611527 Bacon Oct. 31, 1944 

